The field of the invention relates to controlling the wheel slip of a driven wheel coupled to an internal combustion engine.
When a vehicle (such as an automobile, truck or motorcycle) encounters a slippery surface, the engine torque applied to the driven wheel may cause the wheel to abruptly accelerate. A temporary loss in vehicle control may result.
An approach to solving the problem of wheel slip is to control the engine throttle in inverse relation to a measured difference in rotation between the driven wheel and the nondriven wheel. For example, U.S. Pat. No. 4,554,990 discloses a control system wherein the difference in rotation between a driven wheel and a nondriven wheel is used as a feedback variable. The other feedback variables are a signal related to actual throttle position, and a signal related to the throttle position commanded by the vehicle operator.
German patents Nos. 2058819 and 2832739 also disclose control systems for controlling the throttle setting in response to wheel speed sensors.
A problem with the above approaches is that the transient response time of the control system is dependant upon the time delay of transmitting engine torque through the drivetrain and wheels.